Industrial neopentyl glycol (3)

4.

4.

According to the principle of neutralization reaction, the acid content in neopentyl glycol is phenolphthalein as the indicator solution and quantified with sodium hydroxide standard titration solution

4.

a.

b.

c(NaOH)=0.

4.

General laboratory equipment

4.

Weigh about 5g of sample (accurate to 0.

4.

The mass percentage X _{3 of} acid (calculated as acetic acid ) is calculated according to formula (3):

Where: c— the actual concentration of sodium hydroxide standard titration solution, mol/L;

V ₀ —Blank consumption volume of sodium hydroxide standard titration solution, mL;

V—The volume of the standard titration solution of sodium hydroxide consumed by the sample, mL;

m—the mass of the sample, g:

0.

4.

The difference between the two parallel determination results shall not be greater than 0.

4.
4 Determination of melting point range

Under the condition that the room temperature does not exceed 25°C, grind the sample finely and place it in a silica gel desiccator to dry for 24 hours, then perform according to GB617
.

Take the arithmetic mean value as the measurement result
.

4.
4.
1 Allowable difference

The difference between the average value of the initial melting temperature and the final melting temperature measured twice is not more than 1℃
.

4.
5 Determination of moisture

Weigh 1～1.
5g sample (accurate to 0.
0002g), and perform other operations according to GB6283
.

Take the arithmetic mean value as the measurement result
.

4.
5.
1 Allowable difference

The difference between the two determination results shall not be more than 0.
05%
.

5 Inspection rules

5.
1 The neopentyl glycol products should be inspected by the quality inspection department of the manufacturer, and the manufacturer should ensure that all products delivered from the factory meet the requirements of this standard
.

5.
2 Each batch of factory products should be accompanied by a quality certificate in a certain format, including: manufacturer name, product name, grade, batch number, net weight, production date, product quality and standard number
.

5.
3 The user has the right to check and accept in accordance with the provisions of this standard
.

5.
4 Taking the output of each kettle as one batch, sampling shall be carried out in accordance with the provisions of GB6678 and GB6679, and the sampling amount shall not be less than 250g
.

5.
5 Mix the samples taken, divide them into two clean and dry wide-mouth bottles with lids, paste the labels, indicate the product name, sampling date, sampler’s name and batch number, one bottle for analysis and inspection, the other bottle Sealed for two months for future reference
.

5.
6 If one of the indicators in the inspection result does not meet the requirements of this standard, re-sampling from twice the bag for re-inspection
.
Even if one item of the re-inspection result does not meet the requirements, the entire batch of products will be considered unqualified
.

5.
7 When the supply and demand parties have objections to product quality and require arbitration, the arbitration institution may be selected by both parties through negotiation
.
According to the provisions of this standard arbitration verification
.

5.
8 The judgment of the test result shall be carried out according to GB1250 rounding value comparison method, and the rounding shall be carried out according to GB8170
.

6 Marking, packaging, transportation and storage

6.
1 The packaging bag should indicate: manufacturer name, product name, trademark, batch number, number of this standard, net weight and moisture-proof mark
.

6.
2 The neopentyl glycol product uses a plastic film bag inside, a four-layer kraft paper bag and a plastic woven bag or other packaging that can guarantee the quality of the product, and the net weight of each bag is 25kg
.

6.
3 When transporting neopentyl glycol , it should be installed in a covered truck or cabin, and the cabin or cabin should be clean and dry
.

6.
4 Neopentyl glycol should be stored in a dark, dry and clean warehouse, and should not be stacked in the open air
.

Related Links: Industrial Neopentyl Glycol (2)